Architecture

Interest Exchange combines an on-chain fixed-rate protocol with quote discovery and optional automation. The lending position remains in its existing market; Interest Exchange provides the fixed-versus-variable overlay.

Borrowers ── Interface and quote network ── Backers
    │                                         │
    └──────────── On-chain protocol ──────────┘
                         │
                  Lending-market adapters
                         │
                 Existing lending positions

On-chain Contracts

InterestRatePool

InterestRatePool is the source of truth for:

• pool and series creation;
• account-based FRT positions and ERC-6909-style VRT shares;
• reserve, prepaid, origination-bond, and fee accounting;
• fixed-versus-capped-variable settlement;
• crossed-tick sweeps, exits, transfers, and rollovers; and
• account operator permissions.

FRT and VRT do not use a separate production token contract. Their balances and allowances live inside InterestRatePool.

QuoteMarket

QuoteMarket verifies one-shot signed backer quotes. Accepting a quote atomically funds the required reserve and either opens a new fixed-rate position or rolls an existing one.

KeeperBundler

Borrowers can opt into automation with limits they approve. Authorized keepers can maintain prepaid coverage, apply available surplus toward debt, or roll a position within the borrower's selected maturity and rate limits.

Adapter Layer

Adapters give the protocol a consistent view of supported lending markets, including the debt asset and the variable-rate debt index used for settlement. They also support approved debt-management actions without requiring every lending protocol to expose the same interface. See Adapters for the supported-market model.

Off-chain Services

Interface

The interface discovers supported lending positions, displays available maturities and executable quotes, previews opening costs, and prepares the transactions a borrower approves in their wallet.

Quote Network

The quote network broadcasts borrower requests to backers and returns signed, executable responses. It helps participants discover prices but cannot accept a quote or move funds on behalf of a borrower.

Backer Automation

Backers can define pricing and risk limits, respond to eligible requests, and manage available VRT liquidity. Their signed quote remains subject to on-chain validation when a borrower chooses to accept it.

Data and Keepers

Public on-chain events support portfolio and market views. Keepers can advance settlement and perform only the optional automation that users have explicitly authorized. On-chain state remains authoritative for balances, executable quotes, and settlement.